JPH10338746A - Production of polyamide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a semi-aromatic polyamide, enabling to produce the particulate polyamide excellent in various characteristics such as dynamic characteristics, heat resistance, low water absorbability and chemical resistance from raw materials by their one step reaction in a short time. SOLUTION: This method for produce a polyamide comprises polycondensing raw material monomers comprising a dicarboxylic acid component containing 60-100 mol.% of terephthalic acid and a diamine component containing 60-100 mol.% of a 6-18C aliphatic diamine in an organic solvent. Therein, the organic solvent dissolving the produced polymer in an amount of <=0.1 wt.% is used in an amount of >=20 wt.% based on the total amount of the raw materials, and the polymerization is carried out under a temperature condition of 180 deg.C to (Tm-10) deg.C (Tm represents the melting point of the produced polymaide) with stirring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a semi-aromatic polyamide. More specifically, a method capable of producing a finely divided semi-aromatic polyamide having excellent properties such as mechanical properties, heat resistance, low water absorption, and chemical resistance in a one-step reaction from a raw material monomer in a short time. It is about.

[0002]

2. Description of the Related Art Conventionally, polyamides such as nylon 6 and nylon 66 have been widely used as fibers for clothing and industrial materials or as general-purpose engineering plastics because of their excellent properties and ease of melt molding. However, on the other hand, problems such as insufficient heat resistance and poor dimensional stability due to water absorption have been pointed out. In particular, in the field of electric and electronic parts that require heat resistance of reflow soldering due to the recent development of surface mount technology (SMT), or in parts in the engine room of automobiles where the demand for heat resistance is increasing year by year, a conventional polyamide is used. It has become more difficult to use, and there is an increasing demand for polyamides having better heat resistance, dimensional stability, mechanical properties, and physicochemical properties.

[0003] In response to such a demand in the world, various semi-aromatic polyamides containing terephthalic acid and 1,6-hexanediamine as main components have been proposed, and some of them have been put to practical use. However, since the polyamide composed of terephthalic acid and 1,6-hexanediamine has a melting point near 370 ° C., which is higher than the decomposition temperature of the polymer, melt molding is difficult and is not practical. So in practice,
Dicarboxylic acids such as adipic acid and isophthalic acid, or aliphatic polyamides such as nylon 6 are copolymerized in an amount of 30 to 40 mol% to obtain a composition in which the melting point is lowered to a practically usable temperature range, that is, about 280 to 320 ° C. Used.

[0004] As described above, since a semi-aromatic polyamide having high heat resistance is usually used in such a composition that the decomposition temperature and the melting point thereof are close to each other, for example, a batch process which is a conventional general polyamide production method is used. In the case of a formula melt polymerization method or the like, it has been difficult to carry out polymerization without accompanying thermal decomposition of the resulting polyamide to obtain a high molecular weight. Therefore, a polymerization method for a semi-aromatic polyamide in which the decomposition temperature and the melting point are close to each other has been proposed. For example, see JP-A-59-16142.
No. 8 and JP-A-59-155426,
As a method for producing a semi-aromatic polyamide, a low-order condensate formed from an aromatic dicarboxylic acid component unit and an alkylenediamine component unit is subjected to a polycondensation reaction under melt-shearing conditions to form a prepolymer, which is further solid-phased. A method for increasing the degree of polymerization by polymerization is described. In addition, Japanese Unexamined Patent Publication
JP-A-3-8416 describes a method of polymerizing a polyamide salt or a low-order condensate of a polyamide produced by melt polymerization in a specific heat medium.

[0005]

In the above-mentioned method for producing a semi-aromatic polyamide, a solution polymerization method using water as a solvent in the step of producing a low-order condensate is employed.
(1) The reaction temperature is low, the reaction requires a long time, and it is difficult to sufficiently increase the molecular weight of the polyamide. A polymerization step is required; (2) a part of the reaction system may be solidified with an increase in the degree of polymerization, which may make handling difficult; (3) ensuring a polymerization temperature, preventing volatilization of the diamine component, and In order to prevent the reaction system from solidifying, it is necessary to carry out the reaction in a closed system, and since the pressure of the reaction system becomes high due to the steam pressure, it is necessary to use a special container capable of withstanding high pressure as the reaction container; (4) After completion of the reaction, in order to remove the low-order condensate, for example, 10 kg / cm ²
It has to be taken out with a large differential pressure, and there is a problem that handling requires care. In the above-mentioned production method, it is necessary to synthesize a nylon salt or a low-order condensate in advance, and a polymerization reaction is performed in a heat medium using the nylon salt or the low-order condensate prepared in advance. Therefore, the generated polyamide aggregates and does not finely disperse in the heat medium, so that the progress of the polymerization reaction is slow, and it takes a very long time to advance the polymerization reaction to a degree of polymerization sufficient for practical use. In addition, in order to provide the obtained bulk polyamide to a subsequent polymer purification step, a granulation step, or the like, it may be necessary to pass through a separate pulverizing step, which makes the manufacturing process very complicated.

An object of the present invention is to convert a finely divided semi-aromatic polyamide having excellent properties such as mechanical properties, heat resistance, low water absorption and chemical resistance into a one-stage reaction from a raw material monomer by a one-step reaction.
Another object of the present invention is to provide a method that can be manufactured in a short time.

[0007]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, the raw material monomer of polyamide was heated to 180 ° C. in the presence of a specific organic solvent.
Polymerization with stirring at a temperature of (Tm-10) ° C (Tm represents the melting point of the polyamide to be formed) enables a one-step reaction from the raw material monomer, and a high degree of polymerization of the particulate polyamide in a short time. Can be manufactured, and the present invention has been completed.

[0008] That is, the present invention relates to terephthalic acid of 60
~ 100 mol% of dicarboxylic acid and carbon number 6 ~
In a method of producing a polyamide by polymerizing a raw material monomer comprising a diamine containing 60 to 100 mol% of an aliphatic diamine of 18 in the presence of an organic solvent, the amount of polyamide to be dissolved is 0.1% by weight or less. A certain organic solvent is used in an amount of 20% by weight or more based on the total weight of the raw material monomers, and is polymerized with stirring under a temperature condition of 180 ° C. to (Tm−10) ° C. (Tm represents a melting point of the produced polyamide). And a method for producing a polyamide.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The dicarboxylic acid used as a raw material for producing a polyamide must contain terephthalic acid in an amount of from 60 to 100 mol%, preferably from 65 to 100 mol%. When the content of terephthalic acid is 60
If less than mol%, the heat resistance of the resulting polyamide,
Various properties such as chemical resistance are reduced. 40 of dicarboxylic acids
If the proportion is not more than 35 mol%, preferably not more than 35 mol%, dicarboxylic acids other than terephthalic acid, for example, malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, 2-methyladipic acid , Trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid,
Aliphatic dicarboxylic acids such as 3,3-diethylsuccinic acid, azelaic acid, sebacic acid and suberic acid; alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; isophthalic acid;
2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,
4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, diphenic acid, dibenzoic acid, 4,4′-oxydibenzoic acid, diphenylmethane-4,4′-dicarboxylic acid, diphenylsulfone-4,4 One or more aromatic dicarboxylic acids such as' -dicarboxylic acid and 4,4'-biphenyldicarboxylic acid can be used. Of these, aromatic dicarboxylic acids such as isophthalic acid are preferably used. Further, polyvalent carboxylic acids such as trimellitic acid, trimesic acid, and pyromellitic acid can be used together within a range where the obtained polyamide can be melt-molded.

The diamine used as a raw material for the production of polyamide is an aliphatic diamine having 6 to 18 carbon atoms and 60 to 1 of diamine.
It must be contained in an amount of 00 mol%, preferably 75 to 100 mol%, more preferably 90 to 100 mol%. Examples of the aliphatic diamine having 6 to 18 carbon atoms include 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,11-undecanediamine, Linear aliphatic diamines such as 12-dodecanediamine, 3-methyl-1,5-pentanediamine,
2,2,4-trimethyl-1,6-hexanediamine,
2,4,4-trimethyl-1,6-hexanediamine,
2-methyl-1,8-octanediamine, 5-methyl-
Branched aliphatic diamines such as 1,9-nonanediamine; alicyclic diamines such as cyclohexanediamine, methylcyclohexanediamine, isophoronediamine, bis (4-aminocyclohexyl) methane, norbornanedimethylamine and tricyclodecanedimethylamine; And one or more of these can be used. Among these, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,11-undecanediamine, because various properties of the obtained polyamide are excellent. 1,12-dodecanediamine and 2-methyl-1,8-octanediamine are preferred, and 1,9-
More preferably, nonanediamine and 2-methyl-1,8-octanediamine are used in combination. When 1,9-nonanediamine (NMDA) and 2-methyl-1,8-octanediamine (MODA) are used in combination, NMDA: MO
The DA is preferably used at a ratio of 99: 1 to 10:90, more preferably 95: 5 to 20:80. If the proportion of the diamine is 40 mol% or less, preferably 25 mol% or less, more preferably 10 mol% or less, the carbon number is 6
Other diamines other than the aliphatic diamine of ~ 18, for example,
One or more aromatic diamines such as p-phenylenediamine, m-phenylenediamine, xylenediamine, 4,4′-diaminodiphenylsulfone, and 4,4′-diaminodiphenylether can be used.

The organic solvent used in the present invention is not particularly limited as long as the amount of the polyamide produced by the polymerization reaction is 0.1% by weight or less and is chemically stable at the polymerization temperature. Such organic solvents include, for example, xylene, ethylbenzene, mesitylene, pseudocumene, isopropylbenzene, diphenyl ether, biphenyl, dimethylbiphenyl, diethylbiphenyl, trimethylbiphenyl, triethylbiphenyl,
Tripropyl biphenyl, tetraethyl biphenyl, cyclohexyl biphenyl, cyclohexyl benzene, hydrogenated triphenyl, hydrogenated biphenyl, hydrogenated terphenyl, benzyltoluene, isopropyl naphthalene, and the like can be mentioned. One or more of these can be mixed. Can be used. Among these, it is preferable to use xylene, a mixture of diphenyl ether and biphenyl, isopropyl naphthalene, and diphenyl ether.

The amount of the organic solvent to be used is 20 to the total weight of the starting monomers composed of dicarboxylic acid and diamine.
% By weight or more, and preferably 20 to 1900% by weight. If the amount of the organic solvent used is less than 20% by weight based on the total weight of the raw material monomers, the resulting polyamide cannot be finely dispersed in the organic solvent in a fine particle form, and becomes a lump. It decreases significantly.

For the purpose of increasing the polymerization rate and preventing the polyamide formed during the polymerization from deteriorating when the polyamide is polymerized, phosphoric acid, phosphorous acid, hypophosphorous acid, a salt thereof, or an ester thereof is used. Is preferably added to the reaction system. Among these, a hypophosphorous acid derivative is preferred from the viewpoint that the quality of the produced polyamide is excellent, and sodium hypophosphite is particularly preferred from the viewpoint of cost and ease of handling. The addition amount of these phosphorus-based catalysts is preferably 0.01 to 5% by weight based on the total weight of dicarboxylic acid and diamine, and 0.05 to 2% by weight.
%, More preferably 0.07 to 1% by weight.

Further, when polymerizing the polyamide, it is preferable to add a terminal blocking agent for the purpose of controlling the molecular weight and improving the melt stability. The terminal blocking agent is not particularly limited as long as it is a monofunctional compound having reactivity with an amino group or a carboxyl group at a polyamide terminal.
Monocarboxylic acids or monoamines are preferred from the viewpoints of reactivity and stability of the sealed terminal, and monocarboxylic acids are more preferred from the viewpoint of easy handling. In addition, acid anhydrides such as phthalic anhydride, monoisocyanates, monoacid halides, monoesters, and monoalcohols can also be used.

The monocarboxylic acid which can be used as a terminal blocking agent is not particularly limited as long as it has reactivity with an amino group. For example, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid Aliphatic monocarboxylic acids such as acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, and isobutylic acid; alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid; benzoic acid, toluic acid, α- Naphthalene carboxylic acid, β-naphthalene carboxylic acid, methyl naphthalene carboxylic acid, aromatic monocarboxylic acids such as phenylacetic acid,
Alternatively, an arbitrary mixture thereof can be mentioned.
Among these, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, etc. And benzoic acid are particularly preferred.

The monoamine used as the terminal blocking agent is not particularly limited as long as it has reactivity with a carboxyl group. For example, methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine Aliphatic monoamines such as decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine and dibutylamine; cycloaliphatic monoamines such as cyclohexylamine and dicyclohexylamine; aniline, toluidine, diphenylamine,
An aromatic monoamine such as naphthylamine, or an arbitrary mixture thereof can be mentioned. Of these,
From the viewpoints of reactivity, boiling point, stability of the sealed terminal and price, butylamine, hexylamine, octylamine,
Decylamine, stearylamine, cyclohexylamine, aniline are particularly preferred.

The amount of the terminal blocking agent that can be used in producing the polyamide varies depending on the reactivity of the terminal blocking agent used, the boiling point, the reaction apparatus, the reaction conditions, and the like. It can be used within the range of 0.1 to 15 mol% based on the total number of moles.

In the polymerization of polyamide, the raw material monomers of dicarboxylic acid and diamine and, if necessary, the above-mentioned other additives are charged directly into a reaction vessel without passing through a nylon salt, and are charged in the presence of the above-mentioned organic solvent. Need to be polymerized. The step of producing a nylon salt can be omitted by directly polymerizing the raw material monomers in a single step, and the polyamide produced during the polymerization reaction is finely dispersed in fine particles in an organic solvent. A reaction rate is obtained.

The polymerization temperature of the polyamide is 180 ° C.
(Tm-10) ° C. (Tm represents the melting point of the polyamide to be formed), more preferably from 200 ° C. to (Tm-1).
0) ° C. When the polymerization reaction temperature is within this range, a sufficient polymerization rate can be obtained, and a high-quality polyamide excellent in various properties can be obtained. When the polyamide is polymerized, if the temperature is rapidly raised and the polymerization is carried out, the polymerization product may agglomerate. For example, to prevent the agglomeration from occurring, for example, first polymerize at 220 ° C. for several hours. After the polymerization, the polymerization temperature is preferably increased stepwise such that the polymerization is further performed at 230 ° C.

Further, in the polymerization reaction of the polyamide, it is necessary to carry out the polymerization while stirring a mixed solution of the raw material monomer and the organic solvent. The stirring conditions are not particularly limited, but it is preferable to stir under such conditions that the polyamide produced by the polymerization is not agglomerated and finely dispersed in fine particles. In particular, it is preferable to stir under such conditions that 50% by weight or more of the produced polyamide particles have a particle size of 300 μm or less, and 80% by weight or more has a particle size of 3 μm or less.
It is more preferable to stir under conditions such that the thickness is not more than 00 μm. When the particle size of the polyamide particles to be formed is within this range, the polymerization rate is high, a sufficient degree of polymerization is reached in a short time, and the variation in the degree of polymerization is reduced. If the stirring is not performed, the resulting polyamide will be in a lump, causing a decrease in the polymerization rate, and further, a variation in the degree of polymerization will be large.

The polymerization of the polyamide is preferably carried out by heating under an inert gas atmosphere. However, when the diamine has a vapor pressure close to the atmospheric pressure at the polymerization temperature, the molar balance between the dicarboxylic acid and the diamine by volatilization of the diamine is preferred. In order to prevent collapse of the reaction, the initial stage of the reaction is preferably performed in a closed system. When the reaction is carried out in a closed system, the polymerization can be carried out at a considerably lower pressure than the polymerization method using water because the partial pressure of each component in the reaction system is small.

In order to obtain a polyamide having a sufficiently high degree of polymerization, it is preferable to carry out the polymerization reaction while removing water by-produced by the polymerization reaction out of the reaction system. When removing water, the organic solvent is also removed from the reaction system according to the vapor pressure at that temperature, so the amount of the organic solvent is significantly reduced,
When there is a possibility that the generated polyamide may be agglomerated, it is preferable to supplement the organic solvent in an amount corresponding to the amount to be removed in preparing the raw materials or to replenish the organic solvent during the polymerization reaction.

In order to control the reaction rate and degree of polymerization of the polymerization reaction, the amount of water flowing out during the polymerization reaction is measured to estimate the reaction rate, or when the polymerization reaction reaches equilibrium from a change in internal pressure. You can estimate whether or not.

Most of the polyamide produced by the production method of the present invention exists as fine particles not only at the polymerization reaction temperature but also when cooled to around room temperature, so that the produced polyamide can be easily taken out. Rather, it does not need to be crushed again in the subsequent polymer purification step, granulation step, or molding step, and can be used as it is.

The product can be taken out of the reaction vessel as a fluid together with the organic solvent from the lower part of the reaction vessel at the time of heating or after cooling, or it can be easily taken out of the upper part of the reaction vessel. In the solid-liquid separation operation of the mixture of the polyamide and the organic solvent taken out of the reaction vessel, the organic solvent can be removed from the polyamide by filtration or centrifugal elimination. In order to completely remove the organic solvent from the polyamide, for example, after the above-mentioned solid-liquid separation operation, if necessary, by washing with a volatile organic solvent such as methanol, ethanol, acetone, hexane, and then drying under reduced pressure Achieved. It can also be achieved by passing through a vented extruder after the solid-liquid separation operation or after drying under reduced pressure.

In the method for producing a polyamide of the present invention,
Glass fiber, carbon fiber, inorganic powdery filler, organic powdery filler, coloring agent, ultraviolet absorber, light stabilizer, antioxidant, antistatic agent, refractory agent, crystallization accelerator, plasticizer, lubricant, etc. Additives can be added as needed at any stage of the polymerization reaction.

The polyamide obtained according to the present invention can also be used in the form of a reinforcing system containing glass fiber, carbon fiber, inorganic powdery filler, organic powdery filler or the like, or an alloy with another kind of polymer. Various molding methods such as injection molding, blow molding, extrusion molding, compression molding, and vacuum molding can be applied. Furthermore, it can be molded not only into a normal molded product as an engineering plastic, but also into a film or fiber form, and can be suitably used for industrial materials, industrial materials, household goods, and the like.

Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto. The intrinsic viscosity [η], tensile strength,
The tensile elongation, the particle size distribution, and the amount of polyamide dissolved in the organic solvent were measured by the following methods.

Intrinsic viscosity [η]: in concentrated sulfuric acid at 30 ° C.
The intrinsic viscosities (ηinh) of the samples having concentrations of 0.05, 0.1, 0.2, and 0.4 g / dl were measured, and the value obtained by extrapolating the intrinsic viscosity to 0 was defined as the intrinsic viscosity [η].

Tensile strength and tensile elongation: JIS K-7113 using a JIS No. 1 dumbbell type test piece (thickness: 3 mm)
It was measured according to.

Particle size distribution: The particle size was classified using a sieve having openings of 300 μm, and the proportion (% by weight) of the polyamide passing through the sieve was measured.

Dissolution amount of polyamide in organic solvent: 0.1
Weight% polyamide is added to the organic solvent,
Complete dissolution was determined visually. In all of the organic solvents used in the following Examples and Comparative Examples, the polyamide was not completely dissolved, and the amount of the polyamide dissolved was 0.1% by weight or less.

Example 1 65.46 g (0.394 mol) of terephthalic acid, 1,9
-53.82 g (0.34 mol) of nonanediamine, 2-
9.50 g of methyl-1,8-octanediamine (0.0
6 mol), 1.465 g (0.012 mol) of benzoic acid,
0.130 g of sodium hypophosphite monohydrate (0.1% by weight based on the raw material), 95.83 g of diphenyl ether
And 34.55 g of biphenyl were placed in an autoclave having an internal volume of 500 ml, and purged with nitrogen. The internal temperature was raised to 230 ° C. over 2 hours, and the reaction was allowed to proceed for 3 hours. The reaction is always carried out with stirring and the pressure is 5k
The pressure was appropriately released so as not to exceed g / cm ² . After the content was cooled to around room temperature, it was extracted from the autoclave.
After removing the organic solvent using a 4G glass filter, the organic solvent was dried at 200 ° C. under reduced pressure for 12 hours to obtain a polyamide having an intrinsic viscosity [η] of 1.30. 95% by weight of the obtained polyamide had a particle diameter of 300 μm or less.
This polyamide was subjected to a cylinder temperature of 330 ° C and a mold temperature of 1
Injection molding was performed at 00 ° C, and the tensile strength and tensile elongation of the obtained molded article were measured. The results obtained are shown in Table 1 below.

Example 2 91.70 g (0.552 mol) of terephthalic acid, 1,9
-75.35 g (0.476 mol) of nonanediamine, 2
13.30 g of -methyl-1,8-octanediamine
(0.084 mol), 2.052 g (0.01
68 mol), sodium hypophosphite monohydrate 0.182
g (0.1% by weight based on the weight of the raw material), 57.45 g of diphenyl ether and 20.72 g of biphenyl were contained in an inner volume of 5%.
It was placed in a separable flask equipped with a 00 ml reflux condenser and purged with nitrogen. The internal temperature was raised to 230 ° C. over 2 hours while stirring at atmospheric pressure under a nitrogen atmosphere, and the reaction was allowed to proceed for 3 hours. After the content was cooled to around room temperature, it was taken out of the separable flask. After removing the organic solvent using a 4G glass filter, 2 more
After washing with L of methanol and drying at 120 ° C. under reduced pressure for 12 hours, a polyamide having an intrinsic viscosity [η] of 1.25 was obtained. 86% by weight of the obtained polyamide has a particle diameter of 300 μm.
m or less. This polyamide was used at a cylinder temperature of 33.
Injection molding was performed at 0 ° C. and a mold temperature of 100 ° C., and the obtained molded product was measured for tensile strength and tensile elongation. The results obtained are shown in Table 1 below.

Example 3 26.25 g (0.158 mol) of terephthalic acid, 1,9
21.53 g (0.136 mol) of nonanediamine, 2
3.80 g of -methyl-1,8-octanediamine (0.
024 mol), 0.586 g (0.0048 mol) of benzoic acid, 0.052 g (0.1% by weight based on the raw material) of sodium hypophosphite monohydrate, and diphenyl ether 15
3.52 g and 55.35 g of biphenyl were added to an internal volume of 50.
It was placed in a 0 ml autoclave and purged with nitrogen. The internal temperature was raised to 230 ° C. over 2 hours, and the reaction was carried out for 3 hours in a sealed state. The reaction was performed with constant stirring. During the reaction, the pressure showed a maximum of 7 kg / cm ² . After the content was cooled to around room temperature, it was removed from the autoclave. After removing the organic solvent using a 4G glass filter, the mixture was dried at 200 ° C. under reduced pressure for 12 hours to obtain a polyamide having an intrinsic viscosity [η] of 0.96. 88% by weight of the obtained polyamide had a particle diameter of 300 μm or less. This polyamide was heated at a cylinder temperature of 330 ° C.
Injection molding was performed at a mold temperature of 100 ° C., and the tensile strength and tensile elongation of the obtained molded product were measured. The results obtained are shown in Table 1 below.

Example 4 65.46 g (0.394 mol) of terephthalic acid, 1,9
-63.32 g (0.40 mol) of nonanediamine, 1.465 g (0.012 mol) of benzoic acid, 0.130 g (0.1% by weight based on the raw material) of sodium hypophosphite monohydrate and isopropylnaphthalene 130.38 g was placed in an autoclave having an internal volume of 500 ml, and the atmosphere was replaced with nitrogen. Raise the internal temperature to 230 ° C over 2 hours,
The reaction was allowed to proceed for 3 hours. The reaction was carried out with constant stirring, and the pressure was appropriately released so that the pressure did not exceed 5 kg / cm ² . After the content was cooled to around room temperature, it was removed from the autoclave. After removing the organic solvent using a 4G glass filter, the mixture was dried at 200 ° C. under reduced pressure for 12 hours to obtain a polyamide having an intrinsic viscosity [η] of 0.85. 93% by weight of the obtained polyamide had a particle size of 300 μm or less. This polyamide was heated at a cylinder temperature of 330 ° C.
Injection molding was performed at a mold temperature of 100 ° C., and the tensile strength and tensile elongation of the obtained molded product were measured. The results obtained are shown in Table 1 below.

Example 5 45.85 g (0.276 mol) of terephthalic acid, 19.60 g (0.118 mol) of isophthalic acid, 46.48 g (0.40 mol) of 1,6-hexanediamine, 1.benzoic acid 465 g (0.012 mol), 0.113 g of sodium hypophosphite monohydrate (0.1% by weight based on the raw material)
And 113.51 g of diphenyl ether in an internal volume of 50.
It was placed in a 0 ml autoclave and purged with nitrogen. The internal temperature was raised to 230 ° C. over 2 hours, and the reaction was allowed to proceed for 3 hours. The reaction was carried out with constant stirring, and the pressure was appropriately released so that the pressure did not exceed 5 kg / cm ² .
After the content was cooled to around room temperature, it was removed from the autoclave. After removing the organic solvent using a 4G glass filter, the resultant was dried at 200 ° C. under reduced pressure for 12 hours to obtain a polyamide having an intrinsic viscosity [η] of 1.21. 94% by weight of the obtained polyamide had a particle size of 300 μm or less. This polyamide was injection molded at a cylinder temperature of 330 ° C. and a mold temperature of 100 ° C., and the tensile strength and tensile elongation of the obtained molded product were measured. The results obtained are shown in Table 1 below.

Example 6 65.46 g (0.394 mol) of terephthalic acid, 1,9
-53.82 g (0.34 mol) of nonanediamine, 2-
9.50 g of methyl-1,8-octanediamine (0.0
6 mol), 1.465 g (0.012 mol) of benzoic acid,
0.130 g of sodium hypophosphite monohydrate (0.1% by weight based on the weight of the raw material) and 650 g of xylene were added to an internal volume of 2
The mixture was placed in a liter autoclave and purged with nitrogen. After raising the internal temperature to 220 ° C. over 2 hours and reacting for 2 hours, the internal temperature was further raised to 230 ° C. and reacting for 4 hours. The reaction is carried out with constant stirring and the pressure is 7 ~
The pressure was appropriately released so as to be 10 kg / cm ² . After the content was cooled to around room temperature, it was removed from the autoclave. After removing the organic solvent using a 4G glass filter, the mixture was dried at 180 ° C. under reduced pressure for 12 hours to obtain a polyamide having an intrinsic viscosity [η] of 1.30. 95% by weight of the obtained polyamide had a particle size of 300 μm or less. This polyamide was subjected to a cylinder temperature of 330 ° C. and a mold temperature of 10
Injection molding was performed at 0 ° C., and the tensile strength and tensile elongation of the obtained molded article were measured. The results obtained are shown in Table 1 below.

[0039]

[Table 1]

Comparative Example 1 3272.9 g (19.70 mol) of terephthalic acid,
2690.9 g (17.0 mol) of 9-nonanediamine,
474.9 g of 2-methyl-1,8-octanediamine
(3.0 mol), 73.27 g (0.60 mol) of benzoic acid, 6.5 g (0.1% by weight based on the raw material) of sodium hypophosphite monohydrate, and 6 liters of distilled water The autoclave was placed in a 20 liter autoclave and purged with nitrogen.
Stir at 100 ° C. for 30 minutes and raise the internal temperature to 2 over 2 hours.
The temperature was raised to 10 ° C. At this time, the autoclave weighs 22 kg
/ Cm ² . After continuing the reaction for 1 hour, the temperature was raised to 230 ° C., and thereafter, the temperature was maintained at 230 ° C. for 2 hours, and the reaction was performed while gradually removing water vapor and maintaining the pressure at 22 kg / cm ² . Next, the pressure is increased to 10 k for 30 minutes.
g / cm ² and further reacted for 1 hour. Thereafter, the mixture was pulverized, and a polyamide having a particle size of 500 μm to 1690 μm was selected using a sieve, and dried at 100 ° C. under reduced pressure for 12 hours to obtain a low-order condensate having an intrinsic viscosity [η] of 0.25 dl / g. 125 g of the above low-order condensate, 91.88 g of diphenyl ether, and 33.13 g of biphenyl were put in an autoclave having an internal volume of 500 ml, and the atmosphere was replaced with nitrogen. The internal temperature was raised to 230 ° C. over 2 hours, and the reaction was allowed to proceed for 3 hours. The reaction is always carried out with stirring,
The pressure was appropriately released so that the pressure did not exceed 5 kg / cm ² . After the content was cooled to around room temperature, it was removed from the autoclave. After removing the organic solvent using a 4G glass filter, the resultant was dried at 200 ° C. under reduced pressure for 12 hours to obtain a polyamide having an intrinsic viscosity [η] of 0.60. 33% by weight of the obtained polyamide had a particle diameter of 300 μm or less. This polyamide was heated at a cylinder temperature of 330 ° C.
Injection molding was performed at a mold temperature of 100 ° C., and the tensile strength and tensile elongation of the obtained molded product were measured. The results obtained are shown in Table 2 below.

Comparative Example 2 117.82 g (0.709 mol) of terephthalic acid,
96.87 g (0.612 mol) of 9-nonanediamine,
17.10 g of 2-methyl-1,8-octanediamine
(0.108 mol), 2.638 g (0.02 g) of benzoic acid
2 mol), 0.234 g of sodium hypophosphite monohydrate
(0.1% by weight based on raw materials), diphenyl ether 1
9.14 g and 6.90 g of biphenyl were filled with 500
The mixture was placed in a milliliter autoclave and purged with nitrogen.
Raise the internal temperature to 230 ° C over 2 hours,
Allowed to react for hours. The reaction was carried out with constant stirring, and the pressure was appropriately released so that the pressure did not exceed 5 kg / cm ² . After the content was cooled to around room temperature, it was removed from the autoclave. After removing the organic solvent using a 4G glass filter, the resultant was dried at 200 ° C. under reduced pressure for 12 hours to obtain a polyamide having an intrinsic viscosity [η] of 0.38. 24% by weight of the obtained polyamide had a particle diameter of 300 μm or less.
This polyamide was subjected to a cylinder temperature of 330 ° C and a mold temperature of 1
Injection molding was performed at 00 ° C, and the tensile strength and tensile elongation of the obtained molded article were measured. The results obtained are shown in Table 2 below.

Comparative Example 3 65.46 g (0.394 mol) of terephthalic acid, 1,9
-53.82 g (0.34 mol) of nonanediamine, 2-
9.50 g of methyl-1,8-octanediamine (0.0
6 mol), 1.465 g (0.012 mol) of benzoic acid,
0.130 g of sodium hypophosphite monohydrate (0.1% by weight based on the raw material), 95.83 g of diphenyl ether
And 34.55 g of biphenyl were placed in a separable flask having an internal volume of 500 ml and equipped with a reflux condenser, and the atmosphere was replaced with nitrogen. The internal temperature was raised to 160 ° C. over 1 hour while stirring at atmospheric pressure under a nitrogen atmosphere, and the reaction was allowed to proceed for 5 hours. After the content was cooled to around room temperature, it was extracted from the autoclave. After removing most of the heat medium using a 4G glass filter, the mixture was heated at 200 ° C under reduced pressure for 1 hour.
After drying for 2 hours, a polyamide having an intrinsic viscosity [η] of 0.09 was obtained. 87% by weight of the obtained polyamide has a particle size of 30.
It was 0 μm or less. When this polyamide was injection molded at a cylinder temperature of 330 ° C. and a mold temperature of 100 ° C., foaming was remarkable and molding was impossible. The results obtained are shown in Table 2 below.

[0043]

[Table 2]

[0044]

According to the production method of the present invention, mechanical properties,
A finely divided semi-aromatic polyamide having excellent properties such as heat resistance, low water absorption, and chemical resistance can be produced from a raw material monomer in a one-step reaction in a short time.

Claims (1)

[Claims] 1. A raw material monomer comprising a dicarboxylic acid containing 60 to 100 mol% of terephthalic acid and a diamine containing 60 to 100 mol% of an aliphatic diamine having 6 to 18 carbon atoms is polymerized in the presence of an organic solvent. In the method for producing a polyamide by heating, an organic solvent in which the amount of the produced polyamide is 0.1% by weight or less is used at a ratio of 20% by weight or more based on the total weight of the raw material monomers,
A method for producing a polyamide, characterized in that polymerization is carried out with stirring at a temperature condition of ~ (Tm-10) ° C (Tm represents the melting point of the polyamide to be formed).